Improvement of The Anti-Tumor Activity of T-Cells by Modifying the 1G4 TCR

Introduction:

T-cell based immunotherapy for cancer is based on the corollary that tumors express defined antigens which expression may help discriminate between normal and cancerous tissues. One of the most attractive tumor antigens to target is New York Esophageal Squamous Cell Carcinoma-1 (NY-ESO-1) which has been reported to be expressed in a wide range of tumor types, including neuroblastoma, myeloma, metastatic melanoma, synovial sarcoma, etc. It is possible to retarget T-cell specificity by virally transducing them to express a T-cell receptor for a tumor epitope. 1G4 TCR, is an NY-ESO1_154-162 / HLA-A*0201 specific TCR with relatively low/medium anti-tumor reactivity.

Methods:

Based on our previous work aimed at improving TCR stability to enhance its function, we developed in this project a novel 1G4 TCR derivative that we termed- 1G4s, in which we optimized the primary structure, enhanced the stability of the transmembrane region and included selected mutations in the CDR3.

Results:

We examined the influence of improving modifications on the 1G4s-TCR function. We observed increased functionality manifested by higher levels of cytokine secretion (IFNγ, TNFα and IL2), following co-cultures of T-cells engineered to express either the 1G4s TCR compared to those which expressed the wt 1G4-TCR. Furthermore, T-lymphocytes expressing 1G4s-TCR facilitated increased surface expression levels of T-cell activation markers OX40 and 41BB, when compared to the WT. 1G4s also manifested higher functional avidity in the detecting concentration of epitopes in the 10^-9-10^-10M range.

Conclusion:

Overall, we conclude that it possible to manipulate the primary structure of TCRs at several levels to enhance their function. As such, the 1G4s demonstrated a better functional potential than its wt counterpart, leading us to pursue its development as a therapeutic reagent to treat patients with NY-ESO1/HLA-A*0201 positive tumors.